The invention relates to a battery holder which holds a plurality of sealed-type batteries in a bundle.
A prior art battery holder has a structure such as that shown in Japanese Utility Model Publication (Kokai) No. SH060-22752. In the battery holder, a plurality of cylindrical batteries are arranged in such a manner that their peripheral side faces are adjacent to each other, a frame surrounds the periphery of the arranged batteries, and a cover is attached to each of the end faces of the cylindrical batteries through which the positive and negative terminals of the cylindrical batteries are exposed. The frame consists of a side wall surrounding the periphery of the batteries, and a number of partition walls which are inwardly projected from the side wall. The cylindrical batteries are supported by inserting them into the spaces between the side wall and the partition walls, respectively. In some cases, a plurality of holes are formed in a block-like frame and cylindrical batteries are respectively fitted into the holes, or alternatively a large hole having a shape which is obtained by coupling such holes to each other is formed and a plurality of cylindrical batteries are fitted in a bundle into the hole. In the covers, elastic connecting plates are adequately disposed on the faces respectively opposing the end faces of the cylindrical batteries in the frame, so that the cylindrical batteries are electrically connected to each other.
In Japanese Utility Model Publication (Kokai) No. HEI2-99561, proposed is a battery box in which a plurality of battery housing portions are formed by a case outer wall and a case partition wall so as to respectively house a plurality of batteries as one unit. In each of the battery housing portions, a stay is inserted into a center portion of the unit of the plural housed batteries, so that the plural batteries are fixed with being closely contacted with the partition wall.
When a battery is discharged, heat is generated as a result of an internal chemical reaction. In the case of a heavy current drain, particularly, the amount of generated heat is increased. In a sealed-type secondary battery such as a nickel cadmium battery or a nickel-metal hydride battery, the heat generation occurs also when the battery is charged. When the temperature of the battery is raised as a result of the heat generation, self-discharge may reduce the battery capacity or shorten the service life of the battery. Therefore, it is previously determined that such a battery is used in a temperature range of -10 to 60.degree. C. during a discharging process and 0 to 35.degree. C. during a charging process.
In the prior art battery holder, however, each cylindrical battery is surrounded by the frame and both the ends are covered by the covers so that the interior of the holder is substantially hermetically sealed, and hence heat generated from the cylindrical batteries during the discharging or charging process cannot be sufficiently dissipated to the exterior. This produces a problem in that the temperature of the cylindrical batteries may be raised to a level higher than the specified range. In the case where battery packs are to be used, when the battery packs are longitudinally held by a battery holder, a large space is required. In some cases, in order to eliminate this problem, batteries are held by a battery holder so as to constitute a battery pack, and the battery pack is used with being laterally arranged with a number of similar battery packs. When battery packs are to be connected to each other, the connection must be surely conducted so that connecting portions where a terminal is connected to another terminal are not short-circuited. When battery packs are to be connected to each other, furthermore, the connection is requested so to be unaffected by vibration or shock as much as possible. These problems are also applicable to sealed-type batteries of other types such as those of rectangular batteries.